[gentoo-commits] repo/gentoo:master commit in: llvm-core/flang/

[Michał Górny]

commit:     be21871e69498d8fed7011858b0f9cd8cdfa6a64
Author:     Michał Górny <mgorny <AT> gentoo <DOT> org>
AuthorDate: Sat Jun  7 15:35:12 2025 +0000
Commit:     Michał Górny <mgorny <AT> gentoo <DOT> org>
CommitDate: Sat Jun  7 16:32:26 2025 +0000
URL:        https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=be21871e

llvm-core/flang: Build with clang by default

Signed-off-by: Michał Górny <mgorny <AT> gentoo.org>

 llvm-core/flang/flang-21.0.0.9999.ebuild | 24 ++++++++++++++++++++++--
 llvm-core/flang/metadata.xml             |  7 +++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/llvm-core/flang/flang-21.0.0.9999.ebuild 
b/llvm-core/flang/flang-21.0.0.9999.ebuild
index 2561b1b7570e..706f01805d96 100644
--- a/llvm-core/flang/flang-21.0.0.9999.ebuild
+++ b/llvm-core/flang/flang-21.0.0.9999.ebuild
@@ -4,14 +4,14 @@
 EAPI=8
 
 PYTHON_COMPAT=( python3_{11..14} )
-inherit cmake llvm.org python-any-r1
+inherit cmake flag-o-matic llvm.org python-any-r1 toolchain-funcs
 
 DESCRIPTION="LLVM's Fortran frontend"
 HOMEPAGE="https://flang.llvm.org/";
 
 LICENSE="Apache-2.0-with-LLVM-exceptions"
 SLOT="${LLVM_MAJOR}/${LLVM_SOABI}"
-IUSE="+debug test"
+IUSE="+clang +debug test"
 RESTRICT="!test? ( test )"
 
 DEPEND="
@@ -26,6 +26,7 @@ PDEPEND="
        >=llvm-runtimes/flang-rt-${PV}:${LLVM_MAJOR}
 "
 BDEPEND="
+       clang? ( llvm-core/clang )
        test? (
                $(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]')
        )
@@ -39,11 +40,30 @@ python_check_deps() {
        python_has_version "dev-python/lit[${PYTHON_USEDEP}]"
 }
 
+pkg_pretend() {
+       if ! use clang && tc-is-gcc; then
+               ewarn "Building using GCC requires lots of memory (up to 10 GiB 
per process)."
+               ewarn "Consider enabling USE=clang."
+               ewarn "See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119705";
+       fi
+}
+
 pkg_setup() {
        use test && python-any-r1_pkg_setup
 }
 
 src_configure() {
+       if use clang; then
+               # Only do this conditionally to allow overriding with
+               # e.g. CC=clang-13 in case of breakage
+               if ! tc-is-clang ; then
+                       local -x CC=${CHOST}-clang
+                       local -x CXX=${CHOST}-clang++
+               fi
+
+               strip-unsupported-flags
+       fi
+
        local mycmakeargs=(
                -DCMAKE_INSTALL_PREFIX="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}"
 

diff --git a/llvm-core/flang/metadata.xml b/llvm-core/flang/metadata.xml
index 072910296ca3..67d13bc9f0ec 100644
--- a/llvm-core/flang/metadata.xml
+++ b/llvm-core/flang/metadata.xml
@@ -7,4 +7,11 @@
        <upstream>
                <remote-id type="github">llvm/llvm-project</remote-id>
        </upstream>
+       <use>
+               <flag name="clang">
+                       Force building using installed clang (rather than
+                       the default CC/CXX).  This is the default since building
+                       with GCC requires lots of memory.
+               </flag>
+       </use>
 </pkgmetadata>